Homebrew PCBs

--- In Homebrew_PCBs@yahoogroups.com, Simao Cardoso <simaocardoso@...> wrote:
>
> christiansen_alex@... wrote:
> >   
> > hello members 
> > I have a customer that, maybe order a few pcb at me, but 
> > he ask for 105 u copper layer ,singlesided .
> 
> 105µm copper pcb laminates are most known as 3 oz/in².
> About getting it, I am sure that you as a pcb professional can overcome
> that.
> 
> 
> But one useful question comes to mind, How a 3oz board is successfully
> etched? I mean with minor under etch.
> Spray etching is enough? Or etching additives are mandatory? Any
> ideas/experience?
>
No...I dont have any ideas.. think I had some at 70 u many years ago.. and dont remember any difficulties at that time.. it was with tape layout but else the same procedure.

hmmm.. 35 u.. guess thats refer to micrometer.. metric unit..
why would the weight then be expressed in imperial units :):)
alex